Multiquip ST-45HRM manual ST45 Accumulator Circuit, Cleaningthe Lubrication BOX

ST-45 PUMP — MAINTENANCE (PUMP)

CYLINDER LUBRICATION BOX

CAUTION

Before checking lubrication level, stop the engine and remove the engine starter key.

ST45 ACCUMULATOR CIRCUIT

DANGER

1.The lubrication level should be checked everyday prior to pumping and maintained at a height of 5 inches or about ½ the concrete cylinder height. We reccomend a using a soluble type oil (water & oil mixture)

Important notice! During freezing temperatures, completely drain the

NOTE Lubrication Box and cover the hopper after each use. Frozen liquid will restrict the piston travel and cause damage to the pump.

2.As the rubber piston cups naturally wear, fine cement particles will accumulate in the box.Once the concrete paste reaches a height of about ½ inch from the bottom of the box, drain and clean the lubrication box.

CLEANINGTHE LUBRICATION BOX

1.Remove the top cover and the drain plug (Figure 47) located at the bottom of the box and fully drain the inside of the box.

2.Once the box is drained, start the engine and stroke the cylinder (keep hands out of box) ten to fifteen times.

3.While stroking, spray water inside of the box to thoroughly clean out all contamination (Figure 47).

4.When the box is clean replace drain plug, add new lubrication and install the top cover.

Figure 47. Cleaning the Lubrication Box

Improper accumulator charging can result in an explosion causing serious injury or death! NEVER use oxygen or compressed air to charge the accumulator! Only qualified personal should perform this procedure. Use only dry nitrogen to charge the accumulator. Contact your Mayco service department or your local Hydac representative for proper charging procedure.

The accumulator circuit has two functions in the hydraulic system.

■The accumulator circuit furnishes the hydraulic pressure to cycle the shuttle tube.

■The accumulator circuit also furnishes the pilot pressure necessary to activate the hydraulic system.

The accumulator circuit is equipped with a bladder type accumulator (Figure 48) charged with 1100 PSI of dry nitrogen. The accumulator stores one gallon of hydraulic oil, which is, under 1750 PSI of pressure.

Figure 48. Accumulator

When the pump cycles, a part of the stored oil is released to the shuttle cylinder.This pressure release assures the shuttle tube has enough force to shear the cylinder of concrete passing from the concrete cylinder to the concrete delivery line during the cycle phase.

CHECKING ACCUMULATOR BLADDER PRESSURE

The normal accumulator charge pressure should be approximately 1100 PSI.To check the accumulator pressure:

1.Start the engine and stroke the pump. The accumulator pressure gauge (Figure 29) should read 1750 PSI.

2.To determine the actual accumulator PSI, stop the engine and observe the pressure gauge. As the PSI reading slowly decreases, it will reach a point where there will be a sudden drop in the PSI.The PSI reading should be taken just prior to this sudden drop.If you do not read 1100 PSI, the accumulator may require charging or bladder replacement.

PAGE 48 — MAYCO ST-45HRM PUMP — OPERATION & PARTS MANUAL — REV. #4 (07/16/04)